nbc news tehran bureau chief, ali rouzi has the latest. what's the reaction from allies? >> well, that's exactly what they wanted to hear. they wanted to hear from president biden that the united states is back in their partnership with their european allies. a very important partnership that they'll present a unified front, on many subjects. they'll negotiate things together. and the europeans won't be frozen out of any process that the americans want to go forward with, like the nuclear deal. i mean, the europeans were very upset that president trump, basically, pulled out of the deal. he didn't really consult with them. a deal, that was painstakingly negotiated with the europeans and the united states, for over two years. so it's back to business, as usual, with europe. and i think that was music to their ears. and it, also, gives a chance for the europeans, now, to act as a sort of between a very contentious relationship between the united states and iran. look. the -- the reality of the situation is, right now, that the u.s. and iran are at a standoff over the nuclea